package org.yq.tools.encrypt;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;

import org.yq.tools.exception.EncryptException;

/**
 * DES加密
 * 
 * @author yuquan
 * @date 2023-05-02
 * @version 1.0
 */
public class DESUtil {

	/**
	 * 根据参数生成 KEY
	 */
	private static Key getKey(String strKey) {
		Key key = null;
		try {
			KeyGenerator _generator = KeyGenerator.getInstance("DES");
			_generator.init(new SecureRandom(strKey.getBytes()));
			key = _generator.generateKey();
			_generator = null;
		} catch (Exception e) {
			throw new EncryptException("Error initializing SqlMap class. Cause: " + e);
		}
		return key;
	}

	/**
	 * 加密 String 明文输入 ,String 密文输出
	 */
	public static String encrypt(String keyStr, String strMing) {
		byte[] byteMi = null;
		byte[] byteMing = null;
		String strMi = "";
		try {
			byteMing = strMing.getBytes("UTF8");
			byteMi = encryptByte(keyStr, byteMing);
			strMi = Base64.encode(byteMi);
		} catch (Exception e) {
			throw new EncryptException("Error initializing SqlMap class. Cause: " + e);
		} finally {
			byteMing = null;
			byteMi = null;
		}
		return strMi;
	}

	/**
	 * 解密 以 String 密文输入 ,String 明文输出
	 * 
	 * @param strMi
	 * @return
	 */
	public static String decrypt(String keyStr, String strMi) {
		byte[] byteMing = null;
		byte[] byteMi = null;
		String strMing = "";
		try {
			byteMi = Base64.decode(strMi);
			byteMing = decryptByte(keyStr, byteMi);
			strMing = new String(byteMing, "UTF8");
		} catch (Exception e) {
			throw new EncryptException("Error initializing SqlMap class. Cause: " + e);
		} finally {
			byteMing = null;
			byteMi = null;
		}
		return strMing;
	}

	/**
	 * 加密以 byte[] 明文输入 ,byte[] 密文输出
	 * 
	 * @param byteS
	 * @return
	 */
	private static byte[] encryptByte(String keyStr, byte[] byteS) {
		byte[] byteFina = null;
		Cipher cipher;
		try {
			Key key = getKey(keyStr);
			cipher = Cipher.getInstance("DES");
			cipher.init(Cipher.ENCRYPT_MODE, key);
			byteFina = cipher.doFinal(byteS);
		} catch (Exception e) {
			throw new EncryptException("Error initializing SqlMap class. Cause: " + e);
		} finally {
			cipher = null;
		}
		return byteFina;
	}

	/**
	 * 解密以 byte[] 密文输入 , 以 byte[] 明文输出
	 * 
	 * @param byteD
	 * @return
	 */
	private static byte[] decryptByte(String keyStr, byte[] byteD) {
		Cipher cipher;
		byte[] byteFina = null;
		try {
			Key key = getKey(keyStr);
			cipher = Cipher.getInstance("DES");
			cipher.init(Cipher.DECRYPT_MODE, key);
			byteFina = cipher.doFinal(byteD);
		} catch (Exception e) {
			throw new EncryptException("Error initializing SqlMap class. Cause: " + e);
		} finally {
			cipher = null;
		}
		return byteFina;
	}

	/**
	 * 文件 file 进行加密并保存目标文件 destFile 中
	 * 
	 * @param file     要加密的文件 如 c:/test/srcFile.txt
	 * @param destFile 加密后存放的文件名 如 c:/ 加密后文件 .txt
	 */
	public void encryptFile(String keyStr, String file, String destFile) throws Exception {
		Cipher cipher = Cipher.getInstance("DES");
		Key key = getKey(keyStr);
		cipher.init(Cipher.ENCRYPT_MODE, key);
		InputStream is = new FileInputStream(file);
		OutputStream out = new FileOutputStream(destFile);
		CipherInputStream cis = new CipherInputStream(is, cipher);
		byte[] buffer = new byte[1024];
		int r;
		while ((r = cis.read(buffer)) > 0) {
			out.write(buffer, 0, r);
		}
		cis.close();
		is.close();
		out.close();
	}

	/**
	 * 文件采用 DES 算法解密文件
	 * 
	 * @param file     已加密的文件 如 c:/ 加密后文件 .txt *
	 * @param destFile 解密后存放的文件名 如 c:/ test/ 解密后文件 .txt
	 */
	public void decryptFile(String keyStr, String file, String dest) throws Exception {
		Cipher cipher = Cipher.getInstance("DES");
		Key key = getKey(keyStr);
		cipher.init(Cipher.DECRYPT_MODE, key);
		InputStream is = new FileInputStream(file);
		OutputStream out = new FileOutputStream(dest);
		CipherOutputStream cos = new CipherOutputStream(out, cipher);
		byte[] buffer = new byte[1024];
		int r;
		while ((r = is.read(buffer)) >= 0) {
			cos.write(buffer, 0, r);
		}
		cos.close();
		out.close();
		is.close();
	}

}
